RADIAL PERFUSION, DIFFUSION, OXYGEN IN COAXIAL BIOREACTOR: HUMAN HEPATOCYTE LINE

我们开发了一种同轴生物反应器， 肝窦的结构。 它是由聚丙烯 纤维（0.8 mm外径）位于外部聚丙烯纤维（1.8 mm I.D.，2.4 mm o.d），全部包含在5 mm NMR管中。 肝细胞将在2根纤维之间的空间中培养- 环形空间 我们想模拟地球内部的物理化学梯度 想要使用MRM径向测量环 空间（1）有和没有肝细胞灌注和扩散，和 (2)使用全氟癸酸的19 F MRM测定氧浓度。 第一章 内管内腔（毛细血管内空间; ICS）和外纤维周围（毛细血管外间隙; ECS）将 相对于彼此变化，使得介质将从 ECS通过环形空间到达ICS。 然后流速将是 在ECS和ICS之间切换，以显示相反方向的灌注 方向 ECS和ICS之间的整体流量差异将 与径向灌注相关。 三个图像获得使用 对于每一个流量，将获得三个ECS/ICS流量差 方向（即，ECS至ICS; ICS至ECS）-共6张图像。 与 我们相信，在环形空间中的肝细胞将是相干流。 由于组织块施加的阻力而被破坏， 扩散将占主导地位。 在给定ECS/ICS流量差下 对应于从所述测量装置获得的经校准的径向灌注速率， 在上述实验中，我们将测量“表观”扩散 穿过肝细胞团的水系数和/或测量径向 在细胞团的边缘有灌注。 2)氧 浓度将以与径向流相同的方式变化， 通过已通气的ECS和ICS中的灌注介质而变化 分别用40%和20%的氧气加空气。 T1加权19 F 将获得图像，并将其校准到 ECS，其中氧气浓度将通过在线测量 电极上 ECS强度需要根据轴向体积进行校正 流动效应 我将建造一个5转螺线管核磁共振探针， 可以调到1H和19 F。 它会被包裹在 5 mm NMR管，因此FOV = 5 mm。感兴趣区域仅为0.5 mm（环形空间）和50 fm x 50 fm x 200 fm的体素（将 各向异性体素效应相对定量？）将产生10 穿过环形空间的体素。 这10个的绝对强度 将绘制体素以生成3个图形：（1）ECS/ICS流 微分与径向灌注;（2）扩散系数 在一个流速下的细胞质量;（3）穿过细胞的氧浓度。 在一个流速下的细胞质量。 这些数据将适合于确定 功能关系。

We have developed a coaxial bioreactor that mimics the architecture of the liver asinus. It is composed of a polypropylene fiber (0.8 mm o.d.) centered inside an outer polypropylene fiber (1.8 mm i.d., 2.4 mm o.d) all contained inside a 5 mm NMR tube. Hepatocytes will be cultured in the space between the 2 fibers - the annular space. We want to mimic the physico-chemical gradients in the asinus and want to use MRM to measure radially across the annular space (1) perfusion and diffusion with and without hepatocytes, and (2) oxygen concentration using 19F MRM of perflourodecanoic acid. 1) The flow rates in the lumen of the inner tube (intracapillary space; ICS) and around the outer fiber (extracapillary space; ECS) will be varied with respect to each other, such that media will flow from the ECS through the annular space to the ICS. Then flow rates will be switch between ECS and ICS to visualize perfusion in the opposite direction. The difference in bulk flow between the ECS and ICS will be correlated with radial perfusion. Three images obtained using three ECS/ICS flow differentials will be obtained for each flow direction (i.e., ECS to ICS; ICS to ECS) - a total of 6 images. With hepatocytes in the annular space we believe coherent flow will be disrupted due to the resistance imposed by the tissue mass and diffusion will dominate. At a given ECS/ICS flow differential corresponding to a calibrated radial perfusion rate obtained from the experiment described above, we will measure the 'apparent' diffusion coefficient of water across the hepatocyte mass and/or measure radial perfusion at perhaps the fringe of the cell mass. 2) Oxygen concentration will be varied in the same manor that radial flow is varied by perfusing medium in the ECS and ICS that has been aerated with 40% and 20% oxygen plus air, respectively. T1-weighted 19F images will be obtained and will be calibrated to the intensity of the ECS where the oxygen concentration will be measured with an in-line electrode. The ECS intensity will need to be corrected for axial bulk flow effects. I will construct a 5 turn solenoid NMR probe that can be tuned to 1H and 19F. It will be wrapped around the outside of the 5mm NMR tube, so the FOV = 5 mm. The region of interest is only 0.5 mm (the annular space) and a voxel of 50 fm x 50 fm x 200 fm (will an anisotropic voxel effect relative quantitation?) will generate 10 voxels across the annular space. The absolute intensity of these 10 voxels will be plotted to generate 3 graphs: (1) ECS/ICS flow differential versus radial perfusion; (2) diffusion coefficient across the cell mass at one flow rate; (3) oxygen concentration across the cell mass at one flow rate. These data will be fit to determine function relationships.